Connector and method of communication

Abstract

A connector for use with a wirelessly locatable tag and operable to selectively connect the tag to a battery or an auxiliary source. The connector may selective turn the tag on or off. A method and corresponding system for communicating using a plurality of wirelessly locatable tags by selectively turning the tags on and off.

Description

[0001] CONNECTOR AND METHOD OF COMMUNICATION

[0002] Technical Field

[0003] Embodiments relate to a connector for a wirelessly locatable tag and a method of communication using wirelessly locatable tags.

[0004] Background

[0005] Wirelessly locatable tags such as the Apple AirTag and Samsung Smart Tag2 use relatively low power wireless communications protocols such as Bluetooth, Near Field Communication (NFC) and UWB (ultra wide band) to communicate with mobile phones and other portable communication devices. These portable communication devices are connected via a common network so that when one of the portable communication devices is in communication range with the tag, that portable communication device will be able to determine an approximate location of the tag. In this manner, wirelessly locatable tags may be used to locate lost property.

[0006] However, wirelessly locatable tags have some disadvantages. These tags require a power source to operate. Since it is a requirement of the primary application of such tags that they be transportable and they are not intended to be charged, these tags are generally fitted with a battery. However, once that battery loses power, the tag is no longer operational and will not work until the battery has been replaced.

[0007] A further disadvantage is that the use of the tags is generally limited to the proprietary network of the companies who have developed the technology. For example, for a user to use an Apple AirTag, it is necessary to access the network and software developed by Apple. This restricts the use cases for these tags.

[0008] Summary of the Disclosure

[0009] An embodiment provides a connector for use with a wirelessly locatable tag, the wirelessly locatable tag comprising: a battery receptacle having a positive contact for connecting to a positive terminal of a battery and a negative contact for connecting to a negative terminal of a battery, the connector comprising: a positive separator for separating the positive contact from the positive terminal of the battery, and a negative separator for separating the negative contact from the negative terminal of the battery, both the positive and negative separators being adapted to separate the respective contacts from the respective terminals of the battery when the battery is installed in the tag, the connector further comprising a switch connectable to an auxiliary power source so that the switch is operable to selectively provide power to the tag from the battery or the auxiliary power source.

[0010] Either or both the negative separator and the positive separator may comprise two or more conductors separated by at least one insulator.

[0011] The positive and negative separators may be connected to the switch by an electrical lead.

[0012] The electrical lead may be dimensioned to be accommodated by a housing of the tag.

[0013] The electrical lead may be a ribbon cable.

[0014] The housing of the tag may include a cover wherein the cover is configured to accommodate the housing.

[0015] In an embodiment, the tag has a housing to seal the battery and any electronic components of the tag from the environment. The electrical lead may be thin enough to allow the housing to be closed while the separators are in place. In an embodiment the electrical lead is between 0.1 mm and 0.5 mm thick.

[0016] The switch may be further operable to isolate the tag from any power, effectively turning the tag off.

[0017] The switch may comprise a positive switch for switching between positive leads connected to the battery and the auxiliary power source, and a negative switch for switching between negative leads connected to the battery and the auxiliary power source.

[0018] The connector may be adapted to be retrofitted to an existing tag. The tag may then be provided with a cover for a tag housing, wherein the cover is shaped to accommodate the connector. For example, the cover may be shaped to provide an outlet for one or more leads of the connector. The outlet may be weather sealed. A further embodiment extends to a tag fitted with a connector as herein described.

[0019] In certain embodiments, “operationally installed” with reference to the battery being installed in the tag may mean that the tag is operational when the battery is operationally installed or that the tag would be operationally installed if it weren’t for the presence of one or more separator or other component of embodiments.

[0020] A further embodiment extends to a method of communication involving two or more wirelessly locatable tags, the method comprising: selectively connecting each wirelessly locatable tag to a power source so that each wirelessly locatable tag may have a power state which varies between being turned on or off; creating a communication by turning the wirelessly locatable tags on and off; and deciphering said communication by determining whether or not said wirelessly locatable tags are on or off.

[0021] Said communication may comprise varying a power state of one or more of said wirelessly locatable tags over time.

[0022] Said method may comprise designating one of said wirelessly locatable tags as a check tag and maintaining a power state of said check tag in an on state, wherein a signal corresponding to said check tag provides a check which may be used to ensure that communication is occurring.

[0023] Said method may further comprise reading an output of one or more sensors and creating the communication in dependence on the output of the one or more sensors. By linking two or more wirelessly locatable tags to a single controller, the number of possible sensors for a given number of wirelessly locatable tags goes up exponentially due to the advantage of binary number output, each wirelessly locatable tag (T) attached increases the number of possible sensors (S) by a factor of 2, T2=S4. T3=S8. T4=S16, 5=32, 6=64, 7=128, 8=256, 9=512, 10=1024, etc.

[0024] A further embodiment relates to a communication module, the communication module comprising a power source and two or more wirelessly locatable tags, each wirelessly locatable tag being selectively connectable to said power source so that each wirelessly locatable tag has a power state which may be varied between on or off; wherein the communication module further comprises a controller to create a communication by turning the wirelessly locatable tags on and off.

[0025] The communication module may be connected to one or more sensors wherein the controller is adapted to read one or more signals from said sensors and vary said communication according to said signals from said sensors.

[0026] The controller may be adapted to designate one of said wirelessly locatable tags as a check tag the check tag is maintained in a power state of on while the power state of other wirelessly locatable tags is varied.

[0027] Each wirelessly locatable tag may emit a corresponding signal wherein the corresponding signal includes an identifier corresponding to the wirelessly locatable tag.

[0028] Embodiments are herein described, with reference to the accompanying drawings in which:

[0029] Figure 1 is a schematic diagram of a connector according to an embodiment;

[0030] Figure 2 illustrates a connector according to a further embodiment;

[0031] Figure 3 illustrates detail A of Figure 2;

[0032] Figure 4 illustrates the connector of Figure 2 connected to a battery;

[0033] Figure 5 illustrates detail B of Figure 4;

[0034] Figure 6 illustrates exploded details of a case according to an embodiment;

[0035] Figure 7 illustrates the case of Figure 6;

[0036] Figure 8 illustrates a portion of a communications module according to an embodiment;

[0037] Figure 9 illustrates a further portion of the communication module of Figure 8;

[0038] Figure 10 illustrates detail A of Figure 9; Figure 11 illustrates a truck trailer incorporating a communications module according to an embodiment;

[0039] Figure 12 illustrates detail A of Figure 11;

[0040] Figure 13 illustrates detail B of Figure 11;

[0041] Figure 14 illustrates an underside of the trailer of Figure 11;

[0042] Figure 15 illustrates a wheel bearing and hub assembly detail C of Figure 14;

[0043] Figure 16 illustrates a method of communication according to an embodiment; and

[0044] Figure 17 is a schematic illustration of a communication system incorporating an embodiment.

[0045] Detailed Description of Specific Embodiment

[0046] Figure 1 is a schematic diagram of a connector 10 according to an embodiment. The connector 10 operates with a wirelessly locatable tag 12 which is shown here in dashed outline as it is not part of the connector.

[0047] Connectors according to embodiments are intended to work with wirelessly locatable tags such as the Apple AirTag or Samsung Smart Tag2. Furthermore, embodiments may not be limited to these specific types of wirelessly locatable tags and may operate with other wirelessly locatable tags such as the tags sold under the brand name Tile. For ease of reference, “wirelessly locatable tags” are also referred to herein as “tags”.

[0048] The tag 12 comprises a housing 14 for a battery 16. In this implementation, the battery 16 is a button battery and has opposing positive and negative terminals as shown with the '+' and signs in Figure 1. The housing 14 has corresponding a corresponding positive contact 18 and a negative contact 20 which connect to the positive and negative terminals of the battery. It is to be realised that, although the battery 16 has been illustrated as a button battery, embodiments are not limited to button batteries and other types and shapes of batteries are possible too.

[0049] The positive contact 18 and the negative contact 20 are connected to the internal electronics 46 of the tag 12. The internal electronics 46 generally comprise communication electronics such as Bluetooth, NFC and / or UWB transmitters and receivers as well as a processor for executing instructions and memory for storing these instructions. These components are well known and since embodiments are intended to work with pre-existing tags, details of the internal electronics 46 will not be further discussed herein.

[0050] The connector 10 comprises a positive separator 26 and a negative separator 24. The positive separator 26 and the negative separator 24 each comprise a respective conductor (26A and 24 A] which connect to the respective positive 18 and negative 20 contacts of the housing 14 of the wirelessly locatable tag 12. Furthermore, the positive separator 26 and the negative separator 24 each comprise a respective contact (26C and 24C) which connect to the respective positive and negative terminals of the battery 16.

[0051] Both the positive and negative separators comprise a respective insulator 26B and 24B which separates the first conductor from the second conductor.

[0052] The connector 10 further comprises positive leads 30A and 30B, and negative leads 32A and 32B. The positive lead 30B connects to the first conductor 26A of the positive separator 26; the positive lead 30A connects to the second contact 26C of the positive separator; the negative lead 32A connects to the first conductor 24A of the negative separator 24; and the negative lead 32B connects to the second contact 24C of the negative separator 24.

[0053] An auxiliary power source 40 is also provided. In this embodiment, the auxiliary power source 40 is a battery having a positive terminal 42 and a negative terminal 44. The auxiliary power source 40 may be provided as part of the connector of embodiments, or separate therefrom. The connector 10 comprises two switches 34 and 36. Switch 34 is connected to leads 30A and 30B and is connected by lead 38A to the positive terminal 42 of the battery 40. The switch 36 is connected to leads 32A and 32B and is connected by lead 38B to the negative terminal 44 of the battery 40.

[0054] Switch 36 is operable to connect either lead 32A to lead 38B or lead 32B. Similarly, switch 34 is operable to connect either lead 30A or lead 38A to lead 30B. Therefore, by operating the switches 34 and 36 it is possible to switch between power being provided to the internal electronics 46 of the tag 14 by the internal battery 16 or by the external power source 40.

[0055] The connector 10 includes a controller 50 which is able to monitor the output of the internal tag battery 16 and when this output indicates that the battery 16 is running low on power is able to operate switches 34 and 36. It is to be realised that this could also be wired and the controller adapted so that the external battery 40 acts as the main power source and the internal battery 16 acts as the back-up, auxiliary power source.

[0056] In a further embodiment, the switches 34 and 36 are operable to an indeterminate position so that no power is delivered to the tag 14. In this manner, the tag 14 may be turned on and off. In an alternate embodiment, the auxiliary power source 40 is omitted so that as the switches 34 and 36 switch between respective leads 30A and 38A, and 32A and 38A, the device is powered off and on.

[0057] Figure 2 illustrates a portion of a further embodiment of a connector 100 according to an embodiment. Also illustrated in Figure 2 is button battery 102. In this embodiment, the button battery 102 is of the type CR2032, but it is to be realised that other batteries may also be used. The portion of the connector 100 illustrated shows a ribbon cable 112 which contains electrical leads equivalent to the leads 32A, 32B, 30A and 30B of Figure 1.

[0058] The ribbon cable 112 connects to a positive pad 104, to a negative pad 106, positive contact 101 and negative contact 108. The positive pad 104, together with the positive contact is equivalent to the positive separator 26 of Figure 1. The negative pad 106, together with the negative contact 108 is equivalent to the negative separator 24 of Figure 1.

[0059] The positive pad 104 comprises a positive conductor 104a and an insulator 104b. The positive pad 104 has a “T” shaped section 104c that folds down to align itself with the exterior wall of the battery 102. This e “T” shaped section 104c is for battery cases that have side mounted positive terminal contacts of the type illustrated in Figures 5 and 6.

[0060] The negative conductor 108 connects to the negative terminal 102b of the battery 102, and insulator 106b is attached to the conductor 106A.

[0061] When the connector 100 is installed, as illustrated in Figures 4 and 5, the positive contact 101 connects to the positive terminal 102a of the battery 102. The positive contact 101 is sandwiched between the insulator 104b and the positive terminal 102a of the battery 102. The insulator 104b is further connected to the positive conductor 104a which connects to the tag housing as illustrated in Figures 6 Similarly, the negative contact 108 connects to the negative terminal 102b of the battery 102. The negative contact 108 is sandwiched between the insulator 106b and the negative terminal 102b of the battery 102. The insulator 106b is further connected to the negative conductor 106a which connects to the tag housing as illustrated in Figures 6 and 7.

[0062] The other end of the ribbon cable may connect to switches, a controller and auxiliary power source, as illustrated in Figure 1, and as discussed above. As illustrated in Figures 2 and 4, the terminating end 114 and 114’ of the ribbon cable may form part of a larger array.

[0063] Figures 6 and 7 illustrate how a connector 120 as represented in Figures 4 and 5 according to an embodiment is retrofitted to a tag 130. The tag 130 includes a body 132 to which is attached a removable cover 134. The cover 134 is removed to allow for replacement of battery 140 (shown removed in Figure 6). The body 132 includes a battery cradle 136. Although the battery cradle 136 is not generally removeable from the body 132 of the tag 130, it is shown as separate in Figure 6 for ease of reference. The cradle 136 includes negative and positive contacts which, during the usual operation of the tag 130, connect with the negative and positive terminals of the battery 140 or connector 120.

[0064] As shown in the upper portion of Figure 6, the connector 120 is inserted into the battery cradle 136 and the cover 134 is attached to the body 132. . Therefore, in this embodiment, the connector 120 and the top cover 134 form a battery receptacle. The resulting arrangement is shown in Figure 7.

[0065] It is be understood that connectors according to certain embodiments are designed to be retrofitted to existing tags. For this reason, components of the connector such as the ribbon cable 112, positive separator 104, disc 106 and negative pad are thin enough to fit between the battery 102, battery cradle 136 and cover 134. In certain embodiments a new cover may accommodate the cable 112.

[0066] Although the precise dimensions of the components of the connectors of embodiments will depend on the particular application to which the connectors are being put, generally these components will not be more than a couple of millimetres in thickness.

[0067] Figure 8 illustrates a portion of a communications module 150 according to an embodiment. The communications module 150 comprises, in this embodiment, eight tags 160. The number of tags provided may depend on the application. The tags 160 are connected to ribbon cable 162 which terminates in a male ribbon connector 164. The male ribbon connector 164 connects to a controller, illustrated in Figure 9.

[0068] Figure 9 is an exploded view of a controller 170 designed to be interchangeable between different applications of communication modules 204 (as discussed below) and which when operated alongside 204 and forms the switching and logic control of the overall communications module.. Three of the tags 160, the ribbon cable 162 and the male ribbon connector 164 from Figure 8 intended to fit inside controller 170 are also shown in Figure 9. The controller 170 includes a housing 172 having a connector port 174 and an opening 176. A first printed circuit board 178 is fitted with a female ribbon connector 180, able to connect the male ribbon connector 164.The controller 170 can further comprise a second printed circuit board 182 having, in this embodiment, two batteries 184. In this embodiment, the batteries 184 act as the auxiliary power source to the tags 160, as required. The second printed circuit board 182 is connected to the first printed circuit board 178 via ribbon cable 188. The second printed circuit board 182 comprises a USB-C port 190. When the controller 170 is in the operational state, the USB-C port 190 aligns with the openings 176 so that a USB-C connector inserted into the opening 176 engages with the port 190. In this manner, the controller 170 may be connected to one or more sensors.

[0069] In an alternative embodiment, a connector port may comprise multiple ports such as two, three, or more ports. The number of ports will depend on the number of connections the controller is to maintain. For example, the controller may be connected to two, or more, connectors via corresponding USB-C connectors and ports.

[0070] Figure 10 illustrates detail A of Figure 9 and shows four microcontrollers 192 attached to the second printed circuit board and which provide functionality corresponding to the switches 34 and 36, and the controller 50, of Figure 1. Therefore, the microcontrollers 192 are able to switch power for the tags 160 to the auxiliary power source in the form the batteries 184, and to turn any one or more of the tags off or on, as required.

[0071] Figures 11 to 15 illustrates a truck trailer incorporating a communications module according to an embodiment. Figure 11 shows the trailer 200. Figure 12 illustrates detail A of Figure 11. Figure 13 illustrates detail B of Figure 11. Figure 14 illustrates an underside of the trailer of Figure 11 and Figure 15 illustrates detail C of Figure 14. The trailer 200 incorporates a multiple controllers, 170, each of which incorporate three tags 160 similar to those discussed above and one communication module 204. In this setting the multiple controllers are attached to the communication module 204 and work in tandem as both redundancies for each other and enabling larger binary outputs for the end user to allocate and identify various sensor readouts The trailer 200 includes a door sensor 214 attached to a door latching mechanism 206 (Figure 13) and a bearing sensor 208 attached at the end of the axle towards the bearing housing 216 (Figure 15). The door sensor 214 is configured to emit a signal when the door is open. The bearing sensor 208 is configured to emit a signal when the bearing housing 216 exceeds a predetermined temperature. Such sensors are known in the art, for example bi-metallic sensors, and will therefore not be further described herein.

[0072] The sensors 214 and 206 are connected via cables 210 to the controllers 170 via the communications module 204. The communications module receives the output of the sensors 214 and 206 and sends communications using the controllers 170 and the tags 160in the manner described below.

[0073] Figure 16 is a schematic diagram showing a method 400 of communication involving the communications module 204 of Figures 11 to 15. In this example a communication is described involving an output of the door sensor 214. To simplify the process it is assumed that the microcontroller of the communications module 204 has been configured to communicate whether the sensor reflects a state of the door being open or the door being closed. However, it is to be realised that the microcontroller may be configured to create a communication under more sophisticated conditions such as the door being open for longer than a predetermined time or linked to other sensors such as a speed sensor and only issue an alarm if the door is open when the trailer is moving.

[0074] The process of Figure 16 is to be read in conjunction with the communication system 250 illustrated in Figure 17. The communication system 250 comprises the trailer 200 as discussed above. The wireless tags 204, when in the on state, emit a signal which includes an identification indicator. Each indicator is unique to the respective tag. A passing mobile communication device 300 detects the signals emitted by the tags and transmits corresponding information including the identification of the tag detected and an approximate location of the tag, across a communications network to a server 304. The server 304 is configured, using software stored on storage device 306, to receive the information of the signal emitted by the tag, and display information accordingly to a user.

[0075] It is to be realised that the trailer 200, mobile phones 300, network 302 and server 304 are illustrated here by way of example only. Other embodiments may use other mobile communications devices such as tablet computers or smartwatches to detect the signal emitted by the tags of the communication module 204 of the trailer 200. Furthermore, a mobile communications device may be used instead of the server 304. Further changes are possible too.

[0076] Importantly, the mobile phones 300 may belong to complete strangers; the detection of the signal emitted by the tags and forwarding of corresponding information may occur without the knowledge or intervention of a user of the device 300. Therefore, the information relating to the tags may be transmitted by any person with a mobile device able to communicate with the tags. It may, under certain circumstances, be necessary for the mobile devices 300 and the server 304 to communicate using some similar network infrastructure (e.g. it may be necessary that both devices are able to communicate with the Apple iCloud infrastructure).

[0077] However, the operation and details of how wirelessly locatable tags operate is well known and embodiments of the invention use the known system. Certain embodiments may not require any modification to the manner in which such wirelessly locatable tags communicate and operate, as described below with reference to Figures 16 and 17.

[0078] In this embodiment, the communication involves two tags here designated the “check tag” and “tag 1”. It has been found desirable in certain embodiments to include a check tag. Such a check tag may be kept in an always on state. Therefore, the server 304 may be able to determine, when receiving the information corresponding to the check tag, that the communications module 204 is operational and the approximate location of the communications module 204 and therefore obtain an approximate location of the trailer 200.

[0079] The server will then determine if tag 1 is in a power on state or a power off state. In this example, the communications module 204 will only turn on tag 1 when the door sensor indicates that the door is open. If we assume that the door is closed, then at initial step 410, the microcontroller of the communications module 204 will turn tag 1 off. Since the check tag is always on, the communication 412 received by the server 304 will show that only the check tag is on, and that tag 1 is off. The server 304 receives the information from the check tag, but does not receive the information corresponding to tag 1, making the inference that the door is therefore closed and displays this information to the user 414. Furthermore, in this embodiment, the server 304 will indicate to the user that the communications module is operational, and (optionally) provide the user with an approximate, or even precise, location of the communications module. In this manner the server 304 deciphers the communication formed by the microcontroller.

[0080] At the next step executed by the communications module 204, step 416, the door sensor 214 will be read. At the following step, step 418, a determination is made by the microcontroller whether the signal received from the door sensor 214 indicates that the door is open or the door is closed. If it is determined that the signal from the door sensor 214 corresponds to a state where the door is closed, there is no change, and the microcontroller will return to step 410. Under these circumstances, the communication will not be change; the check tag is kept in an on state and tag 1 is kept in an off state, as shown at 412.

[0081] However, if it is determined at step 418 that the signal received from the door sensor 214 indicates that the door is open, then the microcontroller proceeds to step 420 where it will power on tag 1. The communication then changes as shown at 422: both the check tag and tag 1 are on. The server will receive the communication and determine that the door has been open, and display this information to the user at 424.

[0082] In this manner, by turning various wirelessly locatable tags on and off, embodiments are able to convey to a user whether the door of the trailer 200 is open or closed.

[0083] It may be an advantage of certain embodiments that they are able to use the existing wirelessly locatable tag infrastructures to quickly and easily communication information from a sensor to a user.

[0084] It may a further advantage that embodiments of the invention are not reliant on establishing a closed communication channel between the microcontroller on the trailer (for example) and the server (or other device used to communicate with the user).

[0085] Although the operation of the embodiment has been described in simplified terms, it is to be realised that once more tags are used, the method of communication may become more complex. In fact, there are many aspects of binary encoding which apply to certain embodiments. In certain embodiments, certain readouts from certain sensors (for example the bearing sensor 208 detecting a temperature in the bearing 210 which exceeds a predetermined temperature) as an alarm. In the situation where there may be multiple alarms, it may be beneficial to take use of mutual-exclusion (mutex) binary encoding or priority encoding with conflict detection.

[0086] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. In the claims which follow and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments. Similarly, the word “device” is used in a broad sense and is intended to cover the constituent parts provided as an integral whole as well as an instantiation where one or more of the constituent parts are provided separate to one another.

Claims

Claims1. A connector for use with a wirelessly locatable tag, the wirelessly locatable tag comprising: a battery receptacle having a positive contact for connecting to a positive terminal of a battery and a negative contact for connecting to a negative terminal of a battery, the connector comprising: a positive separator for separating the positive contact from the positive terminal of the battery, and a negative separator for separating the negative contact from the negative terminal of the battery, both the positive and negative separators being adapted to separate the respective contacts from the respective terminals of the battery when the battery is operationally installed in the tag, the connector further comprising a switch connectable to an auxiliary power source so that the switch is operable to selectively provide power to the tag from the battery or the auxiliary power source.

2. The connector according to claim 1 wherein either or both the negative separator and the positive separator comprise two or more conductors separated by at least one insulator.

3. The connector according to claim 1 or claim 2 wherein the positive and negative separators are connected to the switch by an electrical lead.

4. The connector according to any of claims 1 to 3 wherein the electrical lead is dimensioned to be accommodated by a housing of the tag.

5. The connector according to claim 4 wherein the electrical lead is a ribbon cable.

6. The connector according to claim 4 or claim 5 wherein the housing of the tag includes a cover and wherein the cover is configured to accommodate the housing.

7. The connector according to any of claims 1 to 4 wherein the tag has a housing to seal the battery and any electronic components of the tag from the environment and wherein the electrical lead is thin enough to allow the housing to be closed while the separators are in place.

8. The connector according to any preceding claim wherein the switch is further operable to isolate the tag from any power, effectively turning the tag off.

9. The connector according to any preceding claim wherein the switch comprises a positive switch for switching between positive leads connected to the battery and the auxiliary power source, and a negative switch for switching between negative leads connected to the battery and the auxiliary power source.

10. The connector according to any preceding claim adapted to be retrofitted to an existing tag.

11. The connector according to claim 10 wherein the tag is provided with a cover for a tag housing to accommodate the connector.

12. A tag fitted with a connector as claimed in any of claims 1 to 11.

13. A method of communication involving two or more wirelessly locatable tags, the method comprising: selectively connecting each wirelessly locatable tag to a power source so that each wirelessly locatable tag may have a power state which varies between being turned on or off; creating a communication by turning the wirelessly locatable tags on and off; and deciphering said communication by determining whether or not said wirelessly locatable tags are on or off.

14. The method of claim 13 wherein said communication comprises varying a power state of one or more of said wirelessly locatable tags over time.

15. The method according to claim 13 or claim 14 wherein said method comprises designating one of said wirelessly locatable tags as a check tag and maintaining a power state of said check tag in an on state, wherein a signal corresponding to said check tag provides a check which may be used to ensure that communication is occurring.

16. The method according to any of claims 13 to 15 further comprising reading an output of one or more sensors and creating the communication in dependence on the output of the one or more sensors.

17. A communication module, the communication module comprising apower source and two or more wirelessly locatable tags, each wirelessly locatable tag being selectively connectable to said power source so that each wirelessly locatable tag has a power state which may be varied between on or off; wherein the communication module further comprises a controller to create a communication by turning the wirelessly locatable tags on and off.

18. The communication module according to claim 17 connected to one or more sensors wherein the controller is adapted to read one or more signals from said sensors and vary said communication according to said signals from said sensors.

19. The communication module according to claim 17 or claim 18 wherein the controller is adapted to designate one of said wirelessly locatable tags as a check tag the check tag is maintained in a power state of on while the power state of other wirelessly locatable tags is varied.

20. The communication module according to any of claims 17 to 19 wherein each wirelessly locatable tag emits a corresponding signal, the corresponding signal including an identifier for the emitting tag.

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